What Is the Excess Energy Availability Score?
When someone consumes more calories than they require, chronic excess energy availability will result in increased body fat storage in two primary areas, called subcutaneous (directly under skin) and visceral (beneath muscle & in and around organs) [1]. Initially, most fat is deposited subcutaneously. This region can be thought of as an energy sink, and once the storage capacity within subcutaneous fat is surpassed (sometimes called the “personal fat threshold”), energy excess begins to spill over into the blood and affect other organ systems [2, 3]. For example, once the subcutaneous capacity becomes overwhelmed, the body begins to store more fat viscerally - both in and around the organs [4]. Visceral fat accumulation has a much larger negative impact on metabolic health than subcutaneous fat [5-8].
Keywords: Excess Energy Availability, Subcutaneous Fat, Metabolic Health
Associated Biomarkers
Experienced Physiological Effects:
- Increased fatigue
- Problems concentrating
- Lower overall mood
Physiology Deep Dive:
Elevated levels of inflammation have been related to an increased risk of injury [5-7]. Higher systemic inflammation can promote muscle atrophy, reduce healing times, increase bone breakdown, and elevate pain signaling [8-11]. Chronically high amounts of muscle damage have also been associated with increased injury risk, potentially due to overwhelming the body’s ability to recover [6, 12, 13]. Decreased levels of iron and vitamin D also appear to elevate the risk of musculoskeletal injuries [14-22]. Clinically low vitamin D is well known to increase bone demineralization, reduce bone mineral density, and is directly related to increased stress fracture risk [23, 24]. Low vitamin D has also been related to impaired muscle regeneration, increased muscular oxidative stress, and attenuated growth pathways potentially elongating the recovery cycle [25, 26]. The relationship between iron deficiency and increased injury risk may be related to low energy availability, which is also known to increase injury risk (ping back to LEA white paper). Along these same lines, reductions in testosterone have also been predictive of increased injury risk [12]. Thus, the injury risk score melds all these biomarkers together into a composite value in order to provide an integrated window into potential injury susceptibility.
Constraint Zones:
Green:
A prolonged period of excess energy availability is unlikely. Metabolic health markers are reassuring, allowing for either ongoing maintenance of current levels of energy intake or moving into a caloric surplus phase if that aligns with the athlete’s goals.
Yellow:
An excess energy availability signal is beginning to appear, and metabolic health markers are starting to be negatively affected. Consider decreasing energy intake and/or increasing energy expenditure. A body composition measurement may be warranted. *Some degree of this signal can be required or expected for some positions in sports that involve building and maintaining higher amounts of body mass [36-39].
Red:
Metabolic dysfunction is evident. A history of prolonged excess energy availability is likely, resulting in likely downstream consequences on other organ systems and causing systemic inflammation. Decreasing energy intake and/or increasing energy expenditure is advisable. A body composition measurement may be warranted. *Some degree of this signal can be required or expected for some positions in sports that involve building and maintaining higher amounts of body mass [36-39].